Monthly variation in conceptions leading to induced abortion

Abortions performed in upper New York State and in New York City over a six‐year period were examined for monthly variation in conception. Significant differences in the month of conception were observed which correlated strongly with monthly conception indices from previous studies of conception leading to illegitimate and legitimate births. Since, for the most part, aborted pregnancies were unwanted, the current findings support the notion that cyclical changes in fecundity may be responsible for seasonality of conception rather than seasonal preferences for marriage followed by an increased risk of conception in the early months after marriage.